Unresolved Billing Dispute going back 7 months

I am a long time AT&T customer  Having been a victim of the recent CA Wildfires  (Dec 4 2017), I called AT&T to see how to we could get more data, we needed it temporarily to get a hold of the necessary agencies, until we were put into permanent housing, otherwise we had an internet data increase on our phones, costing $15 for each Gig, I wanted a cheaper way to get data for the next 2 weeks., Using our phones caused us to go over in DATA that month (Billing period of Dec 2017),

I was told the only way was to get a HOTSPOT, I took their suggestion, I was in a terrible bind, , apparently, this meant a HOT SPOT would be under a 2 yr contract,   

I was happy to receive new info by FEMA

(AT&T was waiving overages for fire victims),

I, immediately, called AT&T and notified them I needed to returned (UNOPENED, NOT ACTIVATED DEVICE) and to cancel service, retroactively.  I was told, they would, they needed to wait for device, but that the cancellation was not a problem and YES AT&T had agreed to waive all overages and accept the cancellation due being a victim of the Wild Fire Dec 4th 2017

I tried to return through store, (they would not do it), finally, after getting mailing label,(I did not have access to printer for another week)  I mailed the HOT SPOT DEVICE through UPS,  I waited, but they never contacted me. 

I called them again, on hold for a long period of time. each call on hold and waiting for help (1-3 hours each time) I was told I would need to talk to Loyalty dept. transferred, lost connection, they hung up?  I Called back again, and this went like this every month (Jan, Feb, Mar, April), and Jan-Mar 2017 I was continually billed for the HOT SPOT, I did not see the cancellation applied or credit for device that was sent, (I had confirmation it was sent), I've been billed over $465 including activation , taxes, etc.  I have been assured by the Customer Service rep that a supervisor would issue a credit to my account. They would not give me their employee number and I would never get the same rep, just have to explain all over again,  I gad no way of seeing what was written down per our conversation, the burden of proof, would I need to record the conversation?  How can I see what they are documentingm I am at their mercy.  IT is crazy.  Any other business would write to you and document the transaction, I have NEVER heard back, I have NEVER seen a credit, the only credits I received were for the 3 overage charges of $15 for each GIGm during the month of the fire,

I have paid my bill on time, for the past 19 years with AT&T , Cellular,AT&T, and this is crazy. 

This has been so frsutrating, leaving me feeling mistreated and ignored. I want to leave go to another company, but not without my credit or refund.  I am tired of getting the run around, I want either a full refund or a full credit, the last call, the rep said the best she could do is a one month credit, that is ridiculous, I was told in Dec, then in Jan, then, in Feb and Mar, I would get a full refund, Switch a bait?  I will not settle for anything less than a FULL refund to my credit card that it was paid on or FULL credit to my account.

I have 7 phone lines on my account (then they added the Hot Spot), at the time, I now have 6 , my son, transferred out.  while, they stopped charging me for the HOT SPOT, that I never activated or used, I was previously charged for for a total 3 months, even though I HAD to asked to have it cancelled in December 2017 even though they received the HOT SPOT device into their inventory one month prior and never STOPPED the Service on my plan, What is that all about?

My next step it to complain to Consumer reporting agencies and then if Necessary, to a radio or TV network to get help.